Alpine ski is a popular outdoor sports activity in normally subfreezing (Celsius-wise) temperatures, whereby a skier wearing elongated skis at his feet descends at variable speeds over the snow-covered slope of a mountain. Upon reaching the valley, the skier can be brought to the mountain peak once again, through conventional power-operated conveying means. Such an up-and-down cycle may be repeated a number of times during a given day.
The power-operated skier conveying means can be generally subdivided into two distinct categories: first, the so-called T-bars, in which the skiers simply board successive open frame members linked to an endless drive cable and slide upwardly along the slope; and second, chair-lifts, teleferics and gondolas, which are supported in airborne fashion by an endless drive cable. The teleferic and the gondolas include closed cabins, through the door of which a few (for the gondola) or several (for the teleferic) skiers may enter and be transported thereinto. The teleferics and gondolas are clearly the most comfortable for the skiers, since they constitute a weatherproof self-enclosed bubble into which the skiers may warm up (through bodily heat convection between skiers) as they are conveyed to the mountain peak; but they entail large capital cost outlays, and this is why such costs can be recouped only in the largest ski centres where they are usually found (e.g. in the Mont Saint Anne ski resort near Quebec City, for gondolas; or in the Jay Peak ski resort in Vermont, for teleferics). Another factor which would prevent otherwise important ski resort centres from investing into airborne cabin type powered ski lift apparatuses is the conditions where the average wind intensity is so high along the mountain slope as to create a swinging cabin condition preventing safe operation of an airborne cabin--this is the case for the otherwise major ski resort centre of Mont Tremblant in northern Quebec.
Therefore, in most situations, not only does the skier sustain a thermal stress during descent, but also during ascent on the T-bar or chair-lift, the more so in the latter (ascent) case in that no heat-generating physical exercise is usually made during ascent, contrarily to the time of descent where the skier will use a large number of different body muscles to achieve a winding pathway along the slopes (as this physical activity per se is tied to his skiing enjoyment). Thus, ascent further contributes to the discomfort of the skier. Moreover, thermal stress does increase with altitude: temperature drops and winds gain speed; it is well known that high winds can substantially decrease the ambient temperature due to the so-called wind-chill factor (as effectively felt by a person's unprotected skin) which is well below the one effectively measured by Hg-based thermometers.
Hence, such compounding of environmental conditions (subfreezing temperature, increased weather harshness--including wind conditions--with increasing altitude, and decreased physical activity during powered ascent from valley to mountain peak) do constitute aggravating factors which compromise the comfort and thus the enjoyment of the skier. In extreme weather conditions, particularly where the temperature falls below the minus twenty degree Celsius mark and where the mountain peak is among the highest of the overall area, the period of time before which the limit threshold of thermal stress resistance is reached by the skier becomes very short, whereby the only remaining recourse for the skier is to undon his skis after each descent--or the like to--get into the heated ski chalet building for a warming period. This obviously reduces the enjoyment of the skier (not to speak of the cost-effectiveness of the purchase of his ski-lift pass), since his total effective skiing time for the given day is reduced.
Clearly, those areas which are first prone to suffer most from the cold are those of the skier's body which are not normally shielded by a thermally insulating fabric layer, i.e. usually the skier's face. Ski goggles can be used to protect part of the face skin exposed to the cold surroundings, but still, the nose and the cheeks usually remain exposed to frostbites. The cartilage-based nose is particularly at risk, because of the scarcity of fat therein and because it projects orthogonally from the face so that often, a nose becomes frostbitten so quickly that this goes unnoticed by the skier since, not feeling anything, he has no clue that such a situation has developed. Unthawing a nose can be a painful experience, or worse. Obviously, skiers may shield their nose with a wool scarf wound around their neck; but, since the scarf does hang ahead of the mouth and nose, it tends to impair breathing of the skier, particularly the heavy breathing associated with the type of skiing performed on the so-called expert (i.e. most challenging) slopes. Moreover, the wool scarf constitutes a screen against which will rebound the air breathed out from the nose, and this backflow of moist air will tend to cloud the otherwise transparent plastic pane of the ski goggles and or prescription glasses, thus compromising the vision--and thus the safety--of the skier.